LOCATION RITTER ORTentative Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, mesic Pachic Haploxerolls
TYPICAL PEDON: Ritter loam, cultivated; on a 5 percent slope at 3,000 foot elevation. (Colors are for dry conditions unless otherwise noted.)
Ap--0 to 4 inches; dark grayish brown (10YR 4/2) loam, very dark brown (10YR 2/2) moist; weak fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine roots; few fine and many very fine irregular pores; neutral (pH 6.9); abrupt smooth boundary. (0 to 8 inches thick)
A1--4 to 11 inches; dark grayish brown (10YR 4/2) loam, very dark brown (10YR 2/2) moist; weak coarse prismatic structure; hard, friable, slightly sticky and slightly plastic; many very fine roots; many very fine tubular pores; neutral (pH 7.0) clear smooth boundary. (2 to 10 inches thick)
A2--11 to 18 inches; dark grayish brown (10YR 4/2) loam, very dark brown (10YR 2/2) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine roots; many very fine tubular pores; neutral (pH 7.2); clear smooth boundary. (5 to 10 inches thick)
AB--18 to 23 inches; brown (10YR 5/3) loam, very dark brown (10YR 2/2) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine roots; many very fine tubular pores; slightly alkaline (pH 7.4); clear smooth boundary. (5 to 10 inches thick)
Bw--23 to 35 inches; brown (10YR 5/3) loam, dark brown (10YR 3/3) moist; weak coarse subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; many very fine roots; many very fine tubular pores; slightly alkaline (pH 7.4); abrupt smooth boundary. (8 to 12 inches thick)
C--35 to 50 inches; brown (10YR 5/3) fine sandy loam, dark brown (10YR 3/3) moist; massive; soft, very friable, nonsticky and nonplastic; many very fine roots; many very fine tubular pores; slightly alkaline (pH 7.6). (10 to 20 inches thick)
R--50 inches; basalt.
TYPE LOCATION: Grant County, Oregon; 2,200 feet south and 2,300 feet west of the NE corner of section 15, T. 8 S., R. 30 E., about .5 mile north of Ritter Road, 4 miles west of junction with U.S. Highway 395. Latitude 44 degrees, 52 minutes, 42 seconds North, Longitude 119 degrees, 05 minutes, 31 seconds West.
RANGE IN CHARACTERISTICS: Depth to basalt bedrock is 40 to 60 inches. The profile is stratified and may or may not contain stone lines. The mean annual soil temperature is 47 to 52 degrees F. Ritter soils are usually moist but dry for 60 to 90 consecutive days at depths of 8 to 24 inches in most years. Mollic epipedon is 20 to 30 inches thick. The particle-size control section has 5 to 15 percent clay and less than 30 percent coarse and very coarse sand.
The A horizon has value of 4 or 5 dry, 2 or 3 moist and chroma of 2 moist and dry. It is slightly acid or neutral.
The AB horizon has value of 4 or 5 dry, 2 or 3 moist and chroma of 2 or 3 moist and dry. It has 1 to 2 percent organic matter.
The Bw and C horizons typically have mollic colors but have less than 1 percent organic matter. The Bw is weak coarse and medium subangular blocky to moderate coarse subangular blocky structure. The C horizon has 0 to 5 percent cobbles and 0 to 20 percent gravel. Reaction for the Bw and C horizon is neutral or slightly alkaline. Texture is loam, sandy loam or fine sandy loam.
COMPETING SERIES: These are the Central Point, Dehill, Doublecreek, Edmundston, Imbler, Oak Glen, and Vernado series. Central Point, Dehill, Doublecreek, Imbler and Oak Glen soils are very deep. Edmundston soils are deep to a paralithic contact and have a mean annual soil temperature of 52 to 59 degrees F. Vernado soils are moderately deep to a lithic contact.
GEOGRAPHIC SETTING: The Ritter soils are on alluvial fans and mountain sideslopes. Slopes are 2 to 50 percent. The Ritter soils have formed in colluvium and alluvium from basalt rocks. The climate is semi-arid with a mean annual precipitation of 14 to 18 inches. The mean annual air temperature is 45 to 50 degrees F. The mean July temperature is about 67 degrees F., and the mean January temperature is about 30 degrees F. The front-free period is 80 to 120 days. The Ritter soils occur at elevations of 2,200 to 4,200 feet.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cupper, Exfo, Hack and Ninetysix soils. Cupper and Hack soils are on fans or plateaus. Cupper soils are ashy over loamy. Hack soils are fine-loamy. Exfo soils are on hillsides and are very shallow to bedrock. Ninetysix soils are on footslopes and are loamy-skeletal.
DRAINAGE AND PERMEABILITY: Well drained; permeability is moderate.
USE AND VEGETATION: Mainly dry cropland. Cereal grains and hay are the major crops. Present vegetation includes antelope bitterbrush, Idaho fescue, bluebunch wheatgrass and basin big sagebrush.
DISTRIBUTION AND EXTENT: East Central Oregon; MLRA 10. The series is inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES PROPOSED: Grant County, Oregon, 1959.
REMARKS: Diagnostic horizons and other features:
Mollic epipedon - from 0 to 23 inches
Cambic horizon - from 23 to 35 inches (lacks organic carbon content for part of mollic)
Xeric soil moisture regime